Get three X’s in a row (horizontal, vertical, or diagonal) before your opponent gets three O’s! 3D knots & crosses is an extension of the classic naughts and crosses game. Playing it well help you see objects in 3-Dimensional space also called “spatial awareness” – plus its also just honest good fun. We like to think the 3D version is more exciting than the basic version where the optimal strategy is easily learned. This is the XL size, not the mini that that is commonly seen on other sites.